The 1988 and 2002 phocine distemper virus epidemics in European harbour seals

Tero Harkonen, Rune Dietz, Peter Reijnders, Jonas Teilmann, Karin Harding, Ailsa Hall, Sophie Brasseur, Ursula Siebert, Simon J. Goodman, Paul D. Jepson, Thomas Dau Rasmussen, Paul Michael Thompson

Research output: Contribution to journalArticle

134 Citations (Scopus)

Abstract

We present new and revised data for the phocine distemper virus (PDV) epidemics that resulted in the deaths of more than 23 000 harbour seals Phoca vitulina in 1988 and 30 000 in 2002. On both occasions the epidemics started at the Danish island of Anholt in central Kattegat, and subsequently spread to adjacent colonies in a stepwise fashion. However, this pattern was not maintained throughout the epidemics and new centres of infection appeared far from infected populations on some occasions: in 1988 early positive cases were observed in the Irish Sea, and in 2002 the epidemic appeared in the Dutch Wadden Sea, 6 wk after the initiation of the outbreak at Anholt Island. Since the harbour seal is a rather sedentary species, such 'jumps' in the spread among colonies suggest that another vector species could have been involved. We discussed the role of sympatric species as disease vectors, and suggested that grey seal populations could act as reservoirs for PDV if infection rates in sympatric species are lower than in harbour seals. Alternatively, grey seals could act as subclinical infected carriers of the virus between Arctic and North Sea seal populations. Mixed colonies of grey and harbour seal colonies are found at all locations where the jumps occurred, It seems likely that grey seals, which show long-distance movements, contributed to the spread among regions. The harbour seal populations along the Norwegian coast and in the Baltic escaped both epidemics, which could be due either to genetic differences among harbour seal populations or to immunity. Catastrophic events such as repeated epidemics should be accounted for in future models and management strategies of wildlife populations.

Original languageEnglish
Pages (from-to)115-130
Number of pages16
JournalDiseases of Aquatic Organisms
Volume68
Issue number2
Publication statusPublished - 30 Jan 2006

Keywords

  • epizootic
  • harbour seal
  • mass mortality
  • phocine distemper virus
  • morbillivirus infection
  • Halichoerus grypus
  • marine mammals
  • Grey seal
  • organochlorine contaminants
  • population dynamics
  • immune response
  • Western Atlantic
  • flame retardants

Cite this

Harkonen, T., Dietz, R., Reijnders, P., Teilmann, J., Harding, K., Hall, A., ... Thompson, P. M. (2006). The 1988 and 2002 phocine distemper virus epidemics in European harbour seals. Diseases of Aquatic Organisms, 68(2), 115-130.

The 1988 and 2002 phocine distemper virus epidemics in European harbour seals. / Harkonen, Tero; Dietz, Rune; Reijnders, Peter; Teilmann, Jonas; Harding, Karin; Hall, Ailsa; Brasseur, Sophie; Siebert, Ursula; Goodman, Simon J.; Jepson, Paul D.; Rasmussen, Thomas Dau; Thompson, Paul Michael.

In: Diseases of Aquatic Organisms, Vol. 68, No. 2, 30.01.2006, p. 115-130.

Research output: Contribution to journalArticle

Harkonen, T, Dietz, R, Reijnders, P, Teilmann, J, Harding, K, Hall, A, Brasseur, S, Siebert, U, Goodman, SJ, Jepson, PD, Rasmussen, TD & Thompson, PM 2006, 'The 1988 and 2002 phocine distemper virus epidemics in European harbour seals', Diseases of Aquatic Organisms, vol. 68, no. 2, pp. 115-130.
Harkonen T, Dietz R, Reijnders P, Teilmann J, Harding K, Hall A et al. The 1988 and 2002 phocine distemper virus epidemics in European harbour seals. Diseases of Aquatic Organisms. 2006 Jan 30;68(2):115-130.
Harkonen, Tero ; Dietz, Rune ; Reijnders, Peter ; Teilmann, Jonas ; Harding, Karin ; Hall, Ailsa ; Brasseur, Sophie ; Siebert, Ursula ; Goodman, Simon J. ; Jepson, Paul D. ; Rasmussen, Thomas Dau ; Thompson, Paul Michael. / The 1988 and 2002 phocine distemper virus epidemics in European harbour seals. In: Diseases of Aquatic Organisms. 2006 ; Vol. 68, No. 2. pp. 115-130.
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AU - Teilmann, Jonas

AU - Harding, Karin

AU - Hall, Ailsa

AU - Brasseur, Sophie

AU - Siebert, Ursula

AU - Goodman, Simon J.

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AU - Rasmussen, Thomas Dau

AU - Thompson, Paul Michael

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N2 - We present new and revised data for the phocine distemper virus (PDV) epidemics that resulted in the deaths of more than 23 000 harbour seals Phoca vitulina in 1988 and 30 000 in 2002. On both occasions the epidemics started at the Danish island of Anholt in central Kattegat, and subsequently spread to adjacent colonies in a stepwise fashion. However, this pattern was not maintained throughout the epidemics and new centres of infection appeared far from infected populations on some occasions: in 1988 early positive cases were observed in the Irish Sea, and in 2002 the epidemic appeared in the Dutch Wadden Sea, 6 wk after the initiation of the outbreak at Anholt Island. Since the harbour seal is a rather sedentary species, such 'jumps' in the spread among colonies suggest that another vector species could have been involved. We discussed the role of sympatric species as disease vectors, and suggested that grey seal populations could act as reservoirs for PDV if infection rates in sympatric species are lower than in harbour seals. Alternatively, grey seals could act as subclinical infected carriers of the virus between Arctic and North Sea seal populations. Mixed colonies of grey and harbour seal colonies are found at all locations where the jumps occurred, It seems likely that grey seals, which show long-distance movements, contributed to the spread among regions. The harbour seal populations along the Norwegian coast and in the Baltic escaped both epidemics, which could be due either to genetic differences among harbour seal populations or to immunity. Catastrophic events such as repeated epidemics should be accounted for in future models and management strategies of wildlife populations.

AB - We present new and revised data for the phocine distemper virus (PDV) epidemics that resulted in the deaths of more than 23 000 harbour seals Phoca vitulina in 1988 and 30 000 in 2002. On both occasions the epidemics started at the Danish island of Anholt in central Kattegat, and subsequently spread to adjacent colonies in a stepwise fashion. However, this pattern was not maintained throughout the epidemics and new centres of infection appeared far from infected populations on some occasions: in 1988 early positive cases were observed in the Irish Sea, and in 2002 the epidemic appeared in the Dutch Wadden Sea, 6 wk after the initiation of the outbreak at Anholt Island. Since the harbour seal is a rather sedentary species, such 'jumps' in the spread among colonies suggest that another vector species could have been involved. We discussed the role of sympatric species as disease vectors, and suggested that grey seal populations could act as reservoirs for PDV if infection rates in sympatric species are lower than in harbour seals. Alternatively, grey seals could act as subclinical infected carriers of the virus between Arctic and North Sea seal populations. Mixed colonies of grey and harbour seal colonies are found at all locations where the jumps occurred, It seems likely that grey seals, which show long-distance movements, contributed to the spread among regions. The harbour seal populations along the Norwegian coast and in the Baltic escaped both epidemics, which could be due either to genetic differences among harbour seal populations or to immunity. Catastrophic events such as repeated epidemics should be accounted for in future models and management strategies of wildlife populations.

KW - epizootic

KW - harbour seal

KW - mass mortality

KW - phocine distemper virus

KW - morbillivirus infection

KW - Halichoerus grypus

KW - marine mammals

KW - Grey seal

KW - organochlorine contaminants

KW - population dynamics

KW - immune response

KW - Western Atlantic

KW - flame retardants

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JO - Diseases of Aquatic Organisms

JF - Diseases of Aquatic Organisms

SN - 0177-5103

IS - 2

ER -